I have to travel a lot for my business, mostly in Europe and Asia, but often in the states to cities like Las Vegas. I used to use sites like Travelocity to book my flights and lodging, but I stumbled upon the better way to find deals: go to the second level sites - those like http://hotelsmixmatch.com who compare the hundreds of different booking sites in one single search. You'll not only see Trivago or Expedia deals, but ALL OF THEM in one place.

I must have saved over 2,000 Euros since I started using them. I sincerely believe that using only one of the top booking sites is not necessarily the best idea.